Causes of high alkaline phosphatase levels include bone conditions, biliary obstructions, leukemia and liver conditions, Medline Plus states. Alkaline phosphatase is an enzyme that comes from several sites across the body. Some physicians may perform this test on its own, or as part of liver screening procedures.
Other causes of high alkaline phosphatase include:
- Bone conditions, including osteoblastic tumors
- People with blood types O and B eating fatty meals
- Paget's disease
Areas of the body that produce alkaline phosphatase include the liver, bones, kidneys, intestines, and in pregnant women, the placenta. As an enzyme it breaks down proteins, but its form depends on the organ producing it. Doctors may measure this enzyme alongside other tests to identify certain conditions. The test usually involves drawing blood without a fasting period. However, if the results are inconclusive, it may be repeated after a 10-hour fasting period. The test is minimally invasive.
The normal range for adults is 25 to 100 ALP per liter of blood, with slightly higher levels for pregnant women because of placental production. In contrast, children have 350 units per liter of blood. In rare cases, high ALP levels can indicate the presence of certain cancers, including kidney cancer. It may also indicate glandular fever/mononucleosis or heart failure.